The present invention relates to an optical pickup for recording information onto an optical recording medium and/or reading out the information from the optical recording medium.
In the prior art, when information needs to be recorded onto a plurality of optical recording mediums different in recording density and/or medium-thickness from each other and/or to be read out from the different optical recording mediums, a plurality of optical system each of which includes a light beam source, a collimator, a light beam splitter, a quarter-wave plate, and an objective for respective recording density and/or medium-thickness are used.
An object of the present invention is to provide an optical pickup device for recording information onto and/or reading out information from an optical recording medium, by which optical pickup device, a thermal conductivity from a light beam source to another element of the optical pickup device is restrained, particularly, the thermal conductivity from the light beam source to a light beam guide member for guiding the light beam after reflected by the optical recording medium toward the light beam detector is restrained, while a positional and attitudinal relationship between the light beam guide member and the light beam source is correctly maintained.
According to the present invention, an optical pickup device for recording information onto and/or reading out information from an optical recording medium, comprises, a light beam source for generating a light beam to be projected toward the optical recording medium, a light beam detector for receiving the light beam reflected by the optical recording medium so that the information is read out from the light beam after reflected by the optical recording medium, a container housing therein the light beam source, and including an aperture through which the light beam generated by the light beam source proceeds toward the optical recording medium, and a light beam guide member mounted on an outer surface of the container and covering the aperture to guide the light beam after reflected by the optical recording medium toward the light beam detector.
Since the container houses therein the light beam source, and includes the aperture through which the light beam generated by the light beam source proceeds toward the optical recording medium, and the light beam guide member is mounted on the outer surface of the container and covers the aperture to guide the light beam after reflected by the optical recording medium toward the light beam detector, the thermal conductivity from the light beam source to another element of the optical pickup device is restrained, particularly, the thermal conductivity from the light beam source to the light beam guide member is restrained while the positional and attitudinal relationship between the light beam guide member and the light beam source is correctly maintained, and the another element of the optical pickup device, for example, the light beam detector is restrained from being affected thermally by a heat energy generated by the light beam source.
The container may be hermetically sealed by the light beam guide member to further restrain the thermal conduction from the light beam source to the another element of the optical pickup device. The light beam generated by the light beam source may pass through the light beam guide member toward the optical recording medium to be reflected by the optical recording medium so that a cross-sectional area of the aperture is minimized.
In order to prevent an optical interference between the light beam before reflected by the recording medium and the light beam after reflected by the recording medium or to restrain the light beam detector from being affected by the light beam before reflected by the recording medium, it is preferable that a direction in which the light beam toward the recording medium proceeds into the light beam guide member is prevented from being substantially parallel to a direction in which the light beam after reflected by the optical recording medium proceeds out of the light beam guide member toward the light beam detector, that a direction in which the light beam proceeds out of the container toward the recording medium is prevented from being substantially parallel to the direction in which the light beam after reflected by the optical recording medium proceeds out of the light beam guide member toward the light beam detector, that the direction in which the light beam proceeds out of the container toward the recording medium is prevented from being substantially parallel to a direction in which the light beam after reflected by the optical recording medium proceeds into the light beam detector, that a direction in which the light beam proceeds out of the light beam guide member toward the recording medium is prevented from being substantially parallel to a direction in which the light beam after reflected by the optical recording medium proceeds out of the light beam guide member toward the light beam detector, that the direction in which the light beam proceeds out of the light beam guide member toward the recording medium is prevented from being substantially parallel to the direction in which the light beam after reflected by the optical recording medium proceeds into the light beam detector, that the direction in which the light beam toward the recording medium proceeds into the light beam guide member and the direction in which the light beam after reflected by the optical recording medium proceeds out of the light beam guide member toward the light beam detector are substantially opposite to each other, that the direction in which the light beam proceeds out of the container toward the recording medium and the direction in which the light beam after reflected by the optical recording medium proceeds out of the light beam guide member toward the light beam detector are substantially opposite to each other, that the direction in which the light beam proceeds out of the container toward the recording medium and the direction in which the light beam after reflected by the optical recording medium proceeds into the light beam detector are substantially opposite to each other, that the direction in which the light beam proceeds out of the light beam guide member toward the recording medium is prevented from being substantially parallel to the direction in which the light beam after reflected by the optical recording medium proceeds out of the light beam guide member toward the light beam detector, that the direction in which the light beam proceeds out of the light beam guide member toward the recording medium is prevented from being substantially parallel to the direction in which the light beam after reflected by the optical recording medium proceeds into the light beam detector, that the direction in which the light beam proceeds out of the light beam guide member toward the recording medium is substantially opposite to the direction in which the light beam after reflected by the optical recording medium proceeds out of the light beam guide member toward the light beam detector, that the direction in which the light beam proceeds out of the light beam guide member toward the recording medium is substantially opposite to the direction in which the light beam after reflected by the optical recording medium proceeds into the light beam detector, that the direction in which the light beam proceeds into the light beam guide member toward the recording medium is prevented from being substantially parallel to the direction in which the light beam after reflected by the optical recording medium proceeds out of the light beam guide member toward the light beam detector, or that the direction in which the light beam proceeds into the light beam guide member toward the recording medium is prevented from being substantially parallel to the direction in which the light beam after reflected by the optical recording medium proceeds into the light beam detector.
The optical pickup device may further comprise another light beam guide member for guiding the light beam generated by the light beam source toward the recording medium. The another light beam guide member may be mounted on the outer surface of the container and covers the aperture. The light beam guide member and the another light beam guide member may be joined with each other. The light beam source and the another light beam source may housed in the container.
The light beam detector may arranged at an outside of the container. The light beam detector may be mounted on the light beam guide member. The another light beam guide member may be housed in the container.
An object of the present invention is to provide an optical pickup device for recording densities and/or recording-medium-thicknesses different from each other, a size of whose optical pickup device is minimized.
An optical pickup device according to the present invention, has a single light beam path in which at least one or either of a plurality of kinds of light beams (different from each other in, for example, wavelength) for the respective recording densities and/or recording-medium-thicknesses proceeds toward a surface of an optical recording medium and proceeds to a light beam detector after being reflected by the surface.
Since the at least one or either of the plurality of kinds of light beams proceeds in the single light beam path in opposite directions, in other words, the single light beam path is used to pass the plurality of kinds of light beams in the opposite directions, a structure and volume between the optical recording medium and light beam emitting elements may be small to minimize the size of the optical pickup device.